1. Field of the Invention
This invention relates to a method of manufacturing a washer, more particularly to an improved method of manufacturing a metal washer.
2. Description of Related Art
A washer is generally used to improve the tightness of a screw fastener. Referring to FIG. 1, conventional washers (A1) are manufactured by punching a metal strip (A) with a punching machine. The scrap portions (T) of the metal strip (A) are discarded. Referring to FIG. 2, in order to increase the material efficiency of the metal strip (A) and to reduce the scrap portion (T), the washers (A1) removed from the metal strip (A) are arranged in three lines, the washers (A) in one line being staggered relative to the washers (A) in the other lines. The washers may be positioned in at least four lines in a similar staggered arrangement. However, the material efficiency of the metal strip (A) is always below 50%. Therefore, the above punching method is inefficient since large amounts of the metal strip (A) are wasted. Correspondingly, the manufacturing costs for the washers (A) are high.